Nature and wildlife photographer Joshua Holko was lucky enough to spend some time with the yet to be announced EF 200-400 f/4L IS 1.4x lens.

Below is a video review with Joshua talking about the lens. I’m travelling home at the time of writing this, and streaming capabilities are minimal so I cannot summarize. From what others have said though, it is receiving high praise for its performance.

If this lens with a 2x tele competes with an 800mm prime super tele, then it has justified its price tag. This lens with the 2x mark iii essentially would allow a photographer to replace a few, several thousand dollar lenses (along with their weight and bulk). Hopefully, this will get some good super teles on the used market with lower prices so us regular folks can afford to pick up a super tele. Not all of us are brain docs ... lookin' at you Neuroanatomist!

If this lens with a 2x tele competes with an 800mm prime super tele, then it has justified its price tag. This lens with the 2x mark iii essentially would allow a photographer to replace a few, several thousand dollar lenses (along with their weight and bulk). Hopefully, this will get some good super teles on the used market with lower prices so us regular folks can afford to pick up a super tele. Not all of us are brain docs ... lookin' at you Neuroanatomist!

Yeah but a 400mm f/4 with a 2x multiplier becomes a 800mm f/8, and not many cameras focus at that aperture, or focus with at most 1 AF point. And to be fair, this would compare to 800mm with a 1.4TC (1120mm f/8)